Lead Acid Battery Introduction

Lead Acid Battery

The lead acid battery is a kind of storage battery. Its anode and cathode are lead and lead oxide respectively, and the electrolyte is a sulfuric acid solution.

A lead acid cell has a nominal voltage of 2.0V, can discharge to 1.5V and charge to 2.4V. Single lead-acid batteries can be connected in series to form 12V, 24V, 36V, 48V, etc.

In discharge state, the main component of the positive electrode is lead dioxide, and the main component of the negative electrode is lead.  

Lead Acid Battery Introduction

Under charging state, the main components of both positive and negative electrodes are lead sulfate.

Pb + 2H+ + 2HSO4— + PbO2 (discharge) <═══> (charge) PbSO4+ 2H2O +PbSO4

Main Components of Lead Accumulator Cell

  • Battery anode plate (lead peroxide.  PbO2) –> Active substance  
  • Cathode plate (spongy lead.  Pb) –> Active substance  
  • Electrolyte (dilute sulfuric acid) –> Sulfuric acid (H2SO4) + water (H2O)  
  • Battery case and cover (PP ABS flame retardant)  
  • Isolation plate (AGM)  
  • The relief valve  
  • Positive and negative poles, positive and negative poles, etc.
Lead Acid Battery Introduction

Lead Acid Battery Types


There are many kinds of lead-acid batteries, which are mainly used in electric vehicle energy storage and solar energy storage systems.  The mainly used lead-acid batteries are flooded lead acid batteries, valve regulated lead acid batteries, GEL lead acid batteries, and so on.  


Flooded Lead acid Battery 


Lead acid battery electrolyte (sulfuric acid) directly involved in the battery charge and discharge reaction process in the conventional lead-acid batteries. This kind of lead acid battery is well known as flooded lead acid Battery. The flooded battery is filled with sulfuric acid electrolyte, and battery plate immerse completely in the sulfuric acid electrolyte.  


The flooded lead acid battery has a cover on top to allow ventilation to block liquid splashes. Due to the loss of evaporation and decomposed water during use, it is necessary to open the cover to regularly add distilled water and adjust the density of the electrolyte, so it is customarily called an “open” battery.

Flooded lead acid battery is characterized by cheap price, long life.

The disadvantage is that the flooded lead acid battery need for frequent maintenance.  


Valve Regulated Lead Acid Battery


Valve regulated lead acid battery, also known as maintenance free sealed lead acid battery, is divided into AGM sealed lead battery and GEL sealed lead battery.  


AGM sealed lead battery

AGM battery, well known as Absorbent Glass Mat, uses pure sulfuric acid solution as electrolyte, most of which exists in the glass fiber membrane, and a part of the electrolyte is absorbed from the inside of the plate.  


AGM type sealed lead batteries have less electrolyte, thicker plates, and lower active material utilization than open batteries, so the discharge capacity of the battery is about 10% lower than that of open batteries.

AGM sealed lead batteries have a lower discharge capacity than today’s colloidal lead batteries.  Compared with the same specifications of the liquid-rich battery, the price is higher and has the following advantages:  

  • Cycle charging capacity is 3 times higher than lead-calcium battery.  
  • Higher capacitance stability in the whole service life cycle, with longer service life.  
  • Stable operation at low temperature.
  • Reduce the risk of environmental pollution (because the acid is 100% sealed).  
  • Maintenance is very simple, reduce deep discharge.  

GEL Lead Acid Battery

Colloidal lead battery (GEL battery), colloid accumulator is the improvement of flooded lead acid battery, with colloidal electrolyte replaced by sulfuric acid electrolyte.

The safety, storage capacity, discharge performance and service life are better than flooded lead acid battery.  The electrolyte is made of silica sol and sulfuric acid. The concentration of sulfuric acid solution is lower than AGM battery, and the amount of electrolyte is more than AGM battery, which is comparable to the rich liquid battery.  The electrolyte exists as a colloid, filling the separator between the positive and negative poles. The sulfuric acid electrolyte is surrounded by a gel and does not flow out of the cell.

The advantage of GEL acid battery

  • Low leakage rate, high safety performance  
  • High electrolyte capacity  
  • Strong performance at low temperature  
  • Consistency is better than AGM  
  • Long battery life

The Uses of Lead Acid Battery

Valve regulated lead-acid battery is a kind of backup energy storage device.

Lead acid battery for electric vehicle

It is mainly used for trucks, forklifts, cars, railway locomotives, marine, and other vehicles.  

UPS Lead acid battery (uninterruptible power supply)

Mainly used for telephone communication, security alarm, emergency lights, electronic equipment and medical equipment, solar, etc.